cp's OEIS Frontend

A205555 Least positive integer j such that n divides k^(k-1)-j^(j-1), where k (as in A205554) is the least positive integer for which there is such a j.

%I A205555 #6 Dec 04 2016 19:46:26
%S A205555 1,1,1,1,3,1,2,1,1,3,3,1,1,3,4,1,4,1,1,3,1,3,2,1,1,1,4,3,8,2,2,4,4,3,
%T A205555 9,1,5,1,1,3,2,1,1,3,4,2,2,1,1,2,4,1,5,6,3,3,1,8,7,1,5,2,1,4,4,2,4,3,
%U A205555 5,9,2,1,8,5,2,1,3,1,7,1,6,2,4,1,3,1,2,3,2,1,1,5,2,2,5,5,4,1,7
%N A205555 Least positive integer j such that n divides k^(k-1)-j^(j-1), where k (as in A205554) is the least positive integer for which there is such a j.
%C A205555  For a guide to related sequences, see A204892.
%e A205555 1 divides 2^(2-1)-1^(1-1) -> k=2, j=1
%e A205555 2 divides 3^(3-1)-1^(1-1) -> k=3, j=1
%e A205555 3 divides 4^(4-1)-1^(1-1) -> k=4, j=1
%e A205555 4 divides 3^(3-1)-1^(1-1) -> k=3, j=1
%e A205555 5 divides 4^(4-1)-3^(3-1) -> k=4, j=3
%t A205555 s = Table[n^(n-1), {n, 1, 120}];
%t A205555 lk = Table[NestWhile[# + 1 &, 1,
%t A205555    Min[Table[Mod[s[[#]] - s[[j]], z], {j, 1, # - 1}]] =!= 0 &], {z, 1, Length[s]}]
%t A205555 Table[NestWhile[# + 1 &, 1,
%t A205555   Mod[s[[lk[[j]]]] - s[[#]], j] =!= 0 &],
%t A205555  {j, 1, Length[lk]}]
%t A205555 (* _Peter J. C. Moses_, Jan 27 2012 *)
%Y A205555 Cf. A204892, A205551.
%K A205555 nonn
%O A205555 1,5
%A A205555 _Clark Kimberling_, Feb 01 2012